Bank analyst Meredith Whitney downgraded JPMorgan Chase (JPM) from outperform to hold, citing concerns that the bank's losses on a controversial London trade could go much deeper than $2 billion.

Whitney, who founded Meredith Whitney Advisory Group and who gained national acclaim for raising early concerns about Citigroup in 2007, said she downgraded JPMorgan in the wake of a risky London trade that cost the bank billions. She noted that all banks continue to struggle when in it comes to raising capital.

Whitney told CNBC rumors have JPMorgan's trading loss as high as $8 billion with some saying $5 billion. "You just have to wait and see what these companies really earn," she told the network. "The fundamentals of the group (banks) are so bad."